The diary of Samuel Pepys

History doesn't unravel, it just heaps up. And once in an academic blue moon a well-kept diary comes along to help dig it out. Three and a half centuries ago, Samuel Pepys, a British tailor's son with an unpronounceable name and an illegible script, crafted such a literary trowel. For nine years he scribbled 11/4 million words in 17th-century shorthand, which are now what is regarded as perhaps the finest journal kept in the English language.

The now-celebrated diary gathered dust for nearly a century on the bookshelves of Pepys's old college in Cambridge, England, until 1825, when the Rev. John Smith transcribed the diarist's hieroglyphics into a readable but abridged version. Hoi polloi in Britain so relished Pepys's ''hunger for the rare and curious'' that the diary became a Victorian best seller, and the literati began mentioning Pepys (pronounced ''peeps'') and Chaucer in the same breath. Because deciphering Pepys's improvised tachygraphy was so difficult, however, his extraordinary chronicle was never published in its entirety - until today.

Marking the 350th anniversary of Pepys's birth and the conclusion of a literary project which has spanned three decades, the University of California Press, in collaboration with Bell & Hyman of London, has just completed the publication of 11 volumes of Pepys's diary, supplemented with commentary from prominent historians. The new edition, according to scholars on both sides of the Atlantic, is one of the most important literary achievements of the century. It does nothing less than throw back the shutters of windows on the 17th century which have been closed since the Restoration.

Rarely do critics of the world unite; the new Pepys text has produced a chorus: ''One of the glories of contemporary English publishing,'' The Times of London hailed it. ''Living details from the greatest sketchbook of any English century,'' cooed The Guardian. The Observer tipped its bowler to Pepys by invoking Horace's ''Exegi monumentum aere perennius,'' which translated without much poetry means, ''Top this, buddy!''

Horace and the huzzahs would have tickled Pepys pink.

''To read Pepys is to be transported immediately into his world,'' writes Robert Latham, one of the diary's two principal editors. ''His diary is not so much a record of events as a recreation of them. Instead of writing a considered narrative . . . Pepys shows us hundreds of scenes from life - civil servants in committee, M.P.'s in debate, concerts of music, friends on a river outing. Events are jumbled together, sermons with amorous assignations, domestic tiffs with national crises. In this perspective, the great personages are reduced to the same dimensions as the rest of us - the King is a tennis player and an amateur of science, the Duke of York a host who recommends a new sauce, the Lord Chancellor an old man who snores during Privy Council meetings. We are the more willing to be persuaded because Pepys was so frank about himself. Anyone so transparently honest about his own failings convinces us that he is a reliable guide on other matters.''

Adds Thomas Barnes, an Oxford-educated professor of history and law at the University of California at Berkeley: ''Pepys's diary is brilliant reportage, the sort of journalism that would win a Pulitzer today. Pepys was the Ernie Pyle and A.J. Liebling of the 17th century. He had the provocative thoughtfulness of Oliver Wendell Holmes Sr., and a capacity to understand the human condition. In a crisis situation there was no one better. Absolutely finely drawn scenes of the Plague of 1665 and the Great Fire of London are all in Pepys. These new 11 volumes are an invaluable source of English history.''

That one man could have witnessed and obsessively recorded - in an era without newspapers - such a tumultuous period in history is staggering. Pepys was just nine years old when Britain's civil war broke out in 1642. He struggled through adolescence during the reign of Oliver Cromwell. He attended Charles I's beheading and Charles II's coronation, carried the canopy for James II's coronation, and was briefly jailed when William and Mary took the throne.

Pepys survived a bubonic plague that took the lives of 100,000 Londoners, and in 1666 his residence narrowly escaped the fire that razed four-fifths of the city, causing more damage to it than any calamity until the German blitz of World War II.

Pepys saw the publication of Thomas Hobbes's ''Leviathan,'' John Milton's ''Paradise Lost,'' and Sir Isaac Newton's ''Principia Mathematica.'' He lived during the founding of the Bank of England, the reopening of London's theaters (with the first appearance of professional actresses), and the appointment of Henry Purcell as organist of Westminster Abbey.

Samuel Pepys's career reads like a Restoration England version of a Horatio Alger story. He came from a long line of yeoman farmers and rose to become secretary of Admiralty affairs, the equivalent of a US secretary of state. Some historians, such as Professor Barnes, believe Pepys is most responsible - more so, even, than Henry VIII - for building the Navy with which Britannia ruled the waves for centuries.

Unfortunately, said Barnes, Pepys is saluted more often for recording history than for making it. Had it not been for Pepys's unprecedented shipbuilding program and his making the naval service more professional, the British might well have lost the Falklands last year, Barnes postulates. The UC historian further sticks his neck out to wager any roving reporter that, had it not been for Pepys and the royal bureaucracy, Queen Elizabeth II might never have visited California this year.

''Pepys,'' said Barnes in his gravelly, staccato voice, ''more than any other single man, made the Royal Navy a potent fighting force. Pepys put through reforms that shook the English Navy out of its 17th-century doldrums. . . . As far as royalty, the diary gives a blow-by-blow account of London when monarchy is trying to reestablish its reputation after 20 years of republican experiment. If it hadn't been for the dampening of the revolutionary fires by Charles II and the bureaucracy represented in Pepys, England might have gone republican after the French Revolution and you wouldn't have seen any Queen Elizabeth II flying into San Francisco a few weeks ago.''

Professor Barnes admits to unorthodox zeal when it comes to Pepys; the historian is iconoclastic to the point of ''mispronouncing'' Pepys's name. Barnes claims to have discovered one of the diarist's direct lineal descendants in London who pronounces the name ''Pep'-iss.'' With good-humored defiance Barnes asserts, ''I definitely prefer 'Pep-iss.' Family tradition and history ought to be followed.''

And so family history follows: Pepys's father, John, was a London tailor who married a washmaid. Samuel was the fifth of their 11 children. He attended Magdalene College, Cambridge, though little is known of his university career except that he wrote a romance called ''Love is a Cheat'' and that on Oct. 21, 1653, he was admonished for having been ''scandalously overseene in drink.''

Two years out of college Pepys married Elizabeth Marchant, the pretty, penniless, 15-year-old daughter of a French Huguenot exile from Anjou. Not a particularly prudent move for a social climber like Pepys, but, we are told, he was love-struck. Pepys was unemployed but, as fortune would have it, his humble family tree was flowered with relatives of minor gentry from Huntingdonshire and Cambridgeshire. A distant cousin, Edward Mountagu, was a high-ranking naval officer (later to become Earl of Sandwich), who hired Pepys as his accountant and personal secretary.

On Jan. 1, 1660, at the age of 27, Pepys began his diary. (His last entry is on May 31, 1669, when the diarist reports that he fears his eyesight is failing.) He was an observant, astute, compulsively systematic bureaucrat. As an undergraduate, he studied Thomas Shelton's system of tachygraphy, the 17 th-century rage in word processing. Like any good secretary today who writes a shopping list in Gregg, Pepys kept his diary in Shelton. To add further secrecy to those passsages which he felt were not fit for ''all the world,'' he wrote in a polyglot cipher embellished with French and Spanish phrases.

After the death of Oliver Cromwell in 1658, England stood leaderless, and, according to Pepys, there were ''great hopes of the king's coming again.'' In May 1660 Pepys set sail with Mountagu's fleet from Dover on the historic voyage to transport the exiled Charles II back from Holland to the British throne. With the stenographic precision and unquenchable joy in life that became his trademark, Pepys gushingly recorded Charles II's coronation, at which the rain ''bedraggled many a fine suit of clothes . . . Imbroidery and diamonds were ordinary among them. . . . So glorious was the show with gold and silver, that we were not able to look at it - our eyes at last being so much overcome with it.''

(The glamour of royalty soon tarnished. Pepys came to find court life ''infinite tedious.'' Six years after Charles was crowned, he wrote: ''How fickle is this man, and how unhappy we (are) like to be!'' He points out with biting irony that while the Dutch burned the English fleet at Medway, the king was hunting moths and dining with Lady Castlemaine.)

In July 1660, on the coattails of Mountagu's being made a Knight of the Garter, Pepys was appointed Clerk of the Acts for the Navy, a top post in the government department with the biggest budget. A cunning businessman, Pepys then cozied up to the king's brother, the Duke of York (later King James II), and began accepting bribes from merchants supplying the Navy. To obtain his clerkship, Pepys bought off a competitor, one Mr. Barlow, with a 100-pound note.

Kickbacks seemed to have been routine among government purchasing agents. On July 30, 1667, Pepys writes of an encounter with a court official, Mr. Cooling, who admitted ''his horse was a bribe, and his boots a bribe; and told us he was made up of bribes . . . and invited me home to his house, to taste his bribe wine.''

During the first two years of his diary, Pepys moves from simple digs on Salisbury Court near Fleet Street to the Navy Office on Seething Lane, which, according to 1660 tax returns, had 48 hearths. When he started his diary he did not own a watch, had never eaten a sirloin steak at home, nor learned to dance. Within a couple years his coffers quickly swelled from a few guineas to 600 pounds, a sizable estate at a time when three pounds was a generous annual wage for a household servant.

The newly reopened theater (Cromwell had closed them) became his passion. Pepys recounts having attended more than 100 plays. On Sept. 8, 1661, he fretted he was ''troubled in mind to think how much of late I have addicted myself to expense and pleasure.'' With his new fortune Pepys also cultivated courtly tastes in jewelry, fashion, girl-watching, books, and painted portraits.

''I do see all the reason to expect a most excellent picture . . . ,'' Pepys tittered in his diary on March 30, 1666, after returning from the house of Mr. Hayls, a painter. Pepys complained, however, that same month that ''I do not fancy that it hath the ayre of my face. . . . I sit to have it (the portrait) full of shadows and do almost break my neck looking over my shoulder to make the posture for him to work by.'' Neverthless, on May 23 he paid Hayls 14 pounds for the portrait, another 25 pounds for the frame, and hung it in his home ''with great pleasure.''

Nearly three decades ago, August Fruge, then director of the University of California Press, played shuttle diplomat. He zipped between California and England to negotiate the complicated publishing contract between Bell & Hyman, Magdalene College, Robert Latham (a Magdalene don), and the other editor, William Matthews, an English professor at UCLA.

Mr. Fruge, now retired, recently recalled one of his memorable visits to Bell & Hyman, the old London publisher situated blocks from Ye Olde Curiosity Shoppe: ''Bell & Hyman had that old Dickensian flavor. You'd walk into the shipping room and find an old man wrappijg books. He would then shout upstairs to the manager, who came down one of those dingy inside stairways. They were old-fashioned and stodgy, but shrewd with money.''

Acccording to Fruge, the two editors were never the best of friends. They worked separately and seemed to enjoy taking potshots at each other across the Atlantic. Nevertheless, they shared a British eccentricity that made them one of the all-time great academic tag teams: Latham, the plodding, meticulous historian in one corner; Matthews, the brilliant, slapdash text-man and shorthand specialist in the other. Latham is now Pepys librarian at Magdalen; Matthews passed on in 1975.

Among the scholars Fruge consulted before taking on the Pepys's publishing project was Brendan O Hehir, a University of California English professor who specializes in 17th-century literature. Professor O Hehir is the biographer of John Dedham, a member of Parliament and minor poet who lived in London at the time of Pepys.

''Pepys's diary is a tremendous help to anyone writing a biography of an English public figure at that time,'' said O Hehir. ''He was an exceptionally vivid diarist who lets you know what's really happening, right down to the new plays of that season. He writes about everything from the Duke of York and his maid to ice skating. We've always known the facts of the period, but Pepys puts life in them. No one else tells us how people looked and what they gossiped about.''

''During his rule,'' O Hehir added, ''Cromwell dressed like one of the Pilgrim Fathers, there was no theater, no dancing, no interest in fashion. But in the 1660s, the theaters started opening, new books were published. Pepys writes of learning to dance at age 30. He tells of men's new interest in fashion and fancy gloves with feathers. He goes out and buys a plum-colored waistcoat.''

Pepys and his plum waistcoat went far. His career culminated with an appointment to the powerful post of secretary of Admiralty affairs and his election to the presidency of the Royal Society. But, as with heroes in the Restoration comedies Pepys so loved, his own good fortune was unjustly eclipsed. Accused of complicity in the Popish Plot and of selling naval secrets to France, Pepys was imprisoned for six weeks in the Tower of London. He was eventually cleared of all charges, though his honor and pride never regained their former sheen.

As a literary figure Pepys remains overshadowed by contemporaries such as Milton, Dryden, John Donne, and Alexander Pope. Pepys was, after all, a closet author who wrote by candlelight. His intentions were modest, perhaps even journalistic, never literary. His diary has no planned plot or climaxes; it is an episodic, disjointed, but brilliant first draft of history. His account of London is more comprehensive even than that of Boswell, who wrote a century later.

V.S. Pritchett once wrote that ''The born diarists are the snails of life: They are secretive and enclosed in their shells.'' Pepys, however, never retreated from the world he recorded. ''He was a bon vivant,'' said Barnes, ''a well-connected patriot at the very center of late Stuart England. Because of his middle position in society, he could look both ways, up and down.''

''Sometimes,'' said Barnes, ''he had his feet in the gutter, sometimes he dined in the company of kings.'' Which, come to think of it, does sound like escargot.